Smile, and the world smiles with you; cry, and you cry alone.
"Cheerful people never lack company, but miserable people are shunned by others."
Source for meaning: Martin H. Manser (2007). The Facts on File Dictionary of Proverbs. Infobase Publishing. p. 163.
Spurgeon, Charles Haddon (June 1968). American proverbs, maxims & folk sayings. Applied Arts. p. 24.